Abstract

L-asparaginase is a key enzyme that degrades asparagine and this aspect of the enzyme has found a dominant role in chemotherapeutic and food processing industry. The aim of the present study is to sequentially optimize L-asparaginase production from newly isolated Aspergillus sp. using agro-industrial residues as solid substrate. In the first stage, through simplex centroid design maximum L-asparaginase activity was observed using a ternary mixture of cotton seed cake (2/3), wheat bran (1/6), and red gram husk (1/6). In the next step, cultivation parameters such as pH, temperature and moisture content were optimized using Box-Behnken design. After 6 days of fermentation using optimized ternary mixture, maximum activity of 12.57 U/mL was obtained at temperature 35 °C, pH-8 and moisture content 70% (v/w). Optimized bounds were further translated to lab-scale tray bioreactor and L-asparaginase activity was found to be 5.41 and 6.67 U/mL in tray bioreactor with 500 g and 1000 g of substrate mixture respectively. L-asparaginase production increased 5 fold through mixture design and 1.3 times increase in enzyme activity was observed with Box-Behnken design. Present work signifies the importance of optimization in the bioprocess industry for complete understanding and evaluation of enzyme production.